Vermaelen could still leave Arsenal

Vermaelen has attracted interest from both United and Barcelona over the summer and his manager has previously shown uncertainty over whether the defender will remain at Emirates Stadium ahead of the new season. Wenger reiterated that view on Friday.

"Vermaelen is injured. It is a possibility that he goes," Wenger said. "If he does [go], we have to replace [him] because he is an important player in our squad."

United manager Louis van Gaal has underlined his club's need to sign defenders this summer after the departures of Rio Ferdinand, Nemanja Vidic and Patrice Evra.

The Dutchman will be allowed to break transfer records when bringing in new signings at Old Trafford, according to the club's executive vice chairman Ed Woodward. However, United are not the only club expected to continue spending on new recruits.

Wenger, having brought in Alexis Sanchez, Calum Chambers, Mathieu Debuchy and David Ospina so far this summer, insists he is not finished in the transfer market.

Wenger added: "I am very happy because I did what I wanted and I am still hoping to do more. It is August 1st [a month before the Sept. 1 deadline]. It is a long time. We are a bit ahead of what we usually do because the availability on the market was bigger than before."

However, he denied speculation that Colombia international Juan Fernando Quintero was flying to London to complete a move from Porto, saying: "That is wrong."

He was less forthright when asked about Sami Khedira -- "I don't want to give you any names" was his response when asked about the Real Madrid midfielder -- but added: "We are not close to signing anyone."